U.S. patent number 5,495,283 [Application Number 08/120,476] was granted by the patent office on 1996-02-27 for cable television video messaging system and headend facility incorporating same.
This patent grant is currently assigned to Albrit Technologies Ltd.. Invention is credited to Alan B. Cowe.
United States Patent |
5,495,283 |
Cowe |
February 27, 1996 |
Cable television video messaging system and headend facility
incorporating same
Abstract
A cable television video messaging system for selectively
overlaying or substituting a desired input message, for example an
Emergency Broadcast System warning, onto multiple channels of a
cable television system having a headend system where multiple
external program signals are channelized by means of individual
channel modulators. This achieved by a digital microprocessor
powered message-management unit programmed to talk to a network of
channel message units, one for each channel. Preferably the channel
message units are also microprocessor powered and include character
generator and channel synchronizer chips. General supervision of a
cable television system's analog domain program distribution system
by digital means is also possible.
Inventors: |
Cowe; Alan B. (Denville,
NJ) |
Assignee: |
Albrit Technologies Ltd.
(Denville, NJ)
|
Family
ID: |
22390551 |
Appl.
No.: |
08/120,476 |
Filed: |
September 13, 1993 |
Current U.S.
Class: |
725/33;
348/E7.054; 725/144 |
Current CPC
Class: |
H04H
20/103 (20130101); H04H 20/59 (20130101); H04H
20/78 (20130101); H04N 7/16 (20130101); H04H
60/93 (20130101) |
Current International
Class: |
H04N
7/16 (20060101); H04H 1/02 (20060101); H04N
007/16 () |
Field of
Search: |
;348/6,8,9,10,11,12,13,563,564 ;358/86 ;455/4.1,5.1,6.1 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Comments Of The Society Of Cable Television Engineers to The FCC.
Jan. 15, 1993.
|
Primary Examiner: Kostak; Victor R.
Assistant Examiner: Grant; Chris
Attorney, Agent or Firm: Handal & Morofsky
Claims
I claim:
1. A cable television video messaging system for selectively
inserting a desired input message into respective program signals
output on multiple channels of a cable television system, said
cable television system having a headend facility where multiple
external program signals are channelized by means of individual
channel modulators having program signal input means and are
exported to a cable network for transmission to a viewing audience,
said video messaging system comprising:
a) a remotely activatable input message decoder to receive, from
multiple sources, incoming message information regarding a video
message to be displayed on at least one channel, said message
decoder decoding message descriptors embedded in or accompanying
said incoming messages;
b) an intelligent message-management device for routing messages to
at least one designated channel according to said message
information and in accordance with system-based instructions;
and
c) a video injector to combine said video message with a baseband
program video signal for said designated channel to produce a
channelized messaged program video signal;
wherein said channelized messaged program video signal is supplied
to said channel modulator program input.
2. A video messaging system according to claim 1 embodied as a
digital supervisory and display management system capable of being
embedded on existing program distribution equipment in a cable
television system's headend facility.
3. A cable television headend program distribution facility having
installed therein a video messaging system according to claim
1.
4. A cable television video messaging system according to claim 1
wherein said channelized messaged program video signal is selected
from the group consisting of a full-screen replacement message, a
stationary screen overlay message, a crawl text overlay message and
a graphics overlay message.
5. A cable television video messaging system according to claim 1
wherein said video injector unit comprises:
a) an input for said baseband video program signal;
b) an output for said messaged program signal;
c) an intelligent processor with data storage to control said video
injector unit and to receive and output a digital message;
d) an image generator to receive said digital message output from
said intelligent processor and to generate said video message from
said received digital message;
wherein said image generator inserts said video message into said
baseband video signal to provide said messaged program signal.
6. A cable television video messaging system according to claim 5
wherein said image generator comprises a character generator to
receive digital characters and output video text characters and a
character delay circuit to generate a crawl text message.
7. A cable television video messaging system for selectively
inserting a desired input message, in crawl text mode, into a
respective program signal output on at least one selected channel
of a multi-channel cable television system, said cable television
system having a headend facility where multiple baseband program
signals are channelized by means of individual channel modulators
having program signal input means and are exported to a cable
network for transmission to a viewing audience, said video
messaging system comprising:
a) a message input to input a digitized text message and to input
at least one channel address for delivery of said digitized text
message;
b) an intelligent message-management device for routing said
digitized text message to said at least one channel address;
and
c) a video injector for each said channel addressed to combine said
digitized text message with a baseband program video signal for
said designated channel to produce a channelized messaged program
video signal, said video injector comprising:
i) a character generator to convert said digitized text message to
a video text message;
ii) timing circuitry to crawl said video text message horizontally
across a television display; and
iii) message insertion circuitry to combine said video text message
with said respective baseband program signal;
wherein said message management unit and each said video injector
unit are interconnected to communicate messages in addressable
digitized network manner and wherein said channelized messaged
program video signal is supplied to a respective channel modulator
program signal input.
Description
TECHNICAL BACKGROUND
The present invention relates to cable television messaging systems
which have the capability to override or supplement standard
programming output to subscribers on one or more selected multiple
channels with an audio message or a video message, or both. More
particularly, the present invention provides a novel system for
disseminating emergency alerting information to the public,
enabling cable television to participate in that is currently known
as the Emergency Broadcast System, in accordance with rules of the
Federal Communications Commission (FCC).
BACKGROUND OF THE INVENTION
In 1992 typical cable television systems or program distributors,
were operating an average of over thirty channels each and many
stations, or rather, systems, fully expect to be operating or
supplying hundreds of channels in the near future. Technical
developments relating to digital data compression and multiplexing
of program channels over optical fiber cables, which are being
installed, promise the availability of thousands of cable
television channels in the not too distant future.
A typical cable television system comprises a program management
and administrative center and what is known as a headend where the
image signal distribution equipment is installed. At the headend,
incoming programs received by various means such as satellite
transmission and antenna pickup, or generated locally and supplied
from tape or over hard wire from a studio, are coordinated and
distributed out to subscribers over individual program channels.
Individual channels typically comprise a channel modulator adapting
the audio and video signals to the appropriate frequency band for
that channel. The channel modulators output into a combining
network that feeds the signal into a cable distribution system for
distribution to subscribers.
Very often, if not usually, the headend operation is remote from
the programming and administrative center and is unattended, being
operated electronically without the presence of a human operator.
The automated operation of the cable television headend, and other
technical considerations, raise difficulties in providing
occasional or periodic override messaging of the output programming
signals on a given channel. The difficulties are compounded if
selective channel messaging, rather than blanket messaging of all
channels, is desired. A particularly important override message is
an emergency alerting signal in audio or video form. Under current
regulations, a television, or radio broadcast station, as a
condition for an FCC license must have a human operator on duty,
and responsible for processing emergency alerts, whenever the
station is on the air. This operator responds to various types of
emergency alerting inputs and actuates the station emergency
messaging in accordance with the operator's judgment, having regard
to established emergency agency rules and station policy.
A customary alert signal, indeed the standard national Emergency
Broadcast System tone is a two-tone signal which is transmitted on
a weekly basis, as a test signal, with a standardized message
alerting the public to the fact that a test of the Emergency
Broadcast System is taking place. This test signal is familiar to
most people in the USA. In the event of a national emergency, for
which the system has, at this writing, never yet been activated, it
can reasonably be expected that all people tuned to a broadcast
television or radio signal will be reached with an audio message
describing the emergency. With the growth of cable television and
cable television programming, large sectors of the population are
viewing non-broadcast channels not accessed by the Emergency
Broadcast System.
Means do exist for transmitting emergency broadcast signals over
the cable television distribution system to viewers. Where the
cable television system is relaying a signal from a television
station broadcasting radio frequency signals over the airwaves, any
emergency signal transmitted by that broadcast station is also
relayed to the cable television subscriber-viewer. However, as
noted above, a typical cable television system includes tens of
non-broadcast channels, supplied for example by tape, by movies, by
local programs created by, or for, special interest groups, and so
on. These viewers are not reached by the Emergency Broadcast
System, unless the cable television system takes measures to
override its non-broadcast programming with emergency alert
information or messages. Lacking such alert information, there may
be serious delays before these non-broadcast channel viewers become
aware of impending natural disasters such as hurricanes, tornadoes
and flash floods, or are alerted to threats to their safety from
riots, prison escapees and the like, or referring to the fears that
gave birth to the Emergency Broadcast System, before they are
notified of military threats, including nuclear missile
attacks.
Noting especially the proliferation of channels, and noting also
the modest size of some cable television systems, (recent data
indicate that over 60% of cable television systems have less than
1,000 subscribers) technical difficulties and significant costs
arise in providing a cable television message override system. It
has been estimated by the Society for Cable Television Engineers
(SCTE) that headend upgrades to handle both audio and video
Emergency Broadcast System signal delivery, based on the equipment
available prior to the present invention, could total nearly half a
billion dollars for the U.S.A. (see, for example, Cablevision p.
15, Jul. 5, 1993, "Revving Up a Test Drive For EBS").
Means also exist for conveying emergency alerts to viewers of
non-broadcast cable television channels but known means are limited
in functionality, are not all-encompassing and do not reach all
viewers.
It is present policy of the FCC to bring all cable television
viewers within the ambit of the Emergency Broadcast System, or of a
renamed nationwide emergency alerting system, and guidelines or
regulations for achieving this aim are expected to be promulgated
shortly. These guidelines include performance parameters for a new
"device" or devices for overriding non-broadcast cable television
channels with emergency alerts. Relevant FCC activities are
proceeding under FO Docket #91-301 and FO Docket #91-171. The
latest publicly available document from the FCC under this heading,
of which applicant is aware, is a "NOTICE OF PROPOSED
RULEMAKING/FURTHER NOTICE OF PROPOSED RULEMAKING" released Oct. 8,
1992 ("NPRM/FNPRM").
On Jan. 15, 1993, a document entitled "COMMENTS OF THE SOCIETY OF
CABLE TELEVISION ENGINEERS" (SCTE Comments) was filed by counsel
for the SCTE, in the aforementioned FCC docketed matters. The SCTE
Comments describe existing Emergency Broadcast System technology
for cable television and remark upon the FCC's proposals as to
possible performance criteria that might be attained by new
equipment. The comments are apparently the collective input of
those skilled in the art of cable television engineering, being
members of the SCTE. This document apparently represents the state
of the art of this topic at Jan. 15, 1993.
Programming override equipment for emergency alert messaging, as
currently installed in cable television headend facilities, is
described in Appendix A of the SCTE COMMENTS, which information is
summarized herein by reference to FIGS. 1 and 2 of the accompanying
drawings.
FIG. 1 is a schematic depiction of what is known as a
"carrier-substitution method" for emergency alert messaging on
cable television systems. This carrier-substitution method is
widely utilized in currently operating cable television Emergency
Broadcast System equipment, according to the SCTE. The alternative
method is known as "channelized override", and is described with
reference to FIG. 2.
Referring to FIG. 1, carrier-substitution systems employ a group of
substitution carriers 10, one for each channel, which are
referenced 10, to replace the cable television's headend carriers
during an emergency notification.
Substitution carriers 10 are coupled to receive audio from a
telephone answering device 12, and are available on standby as an
alternative to a headend system 14, providing normal programming to
the cable system through a switch control 16.
In the event of an emergency, an authorized official appointed by
the cable television system calls the cable television headend over
a standard, DTMF, touch-tone telephone which activates the
telephone answering device 12.
Entry of appropriate codes causes the telephone answering device 12
to operate switch control 16 replacing the programming signals from
the headend system with the substitution carriers 10 and feeding
them out over the cable system to subscriber-viewers. Depending
upon the system, the official's voice can be fed across the
telephone lines to modulate the substitution carriers. Viewers of
every channel hear the official's message as voice-modulated audio
is input to the cable system. At the same time, video on every
channel is overridden with a black or blank screen. The message
terminates with deactivation by the official entering a turn-off
code or hanging up the telephone.
In summary, this commonly used carrier substitution system
completely replaces the program signal, eliminating all video from
the viewer's screen. This is undesirable, unduly dramatic and may
cause many viewers to panic, fearing the emergency has already
affected their television reception. The audio only option is to
feed the official's voice to all channels; which may override more
detailed, more accurate or more relevant warnings carried by
broadcast channels that are being relayed on the cable television
system.
The channelized override system of the prior art shown in FIG. 2 is
also activated by a touch-tone telephone to which a telephone
answering device 12 responds, activating switch control 16 in
response to the proper touch-tone code, whereupon the telephone
audio message overrides the program audio on all channels. In this
case, in contrast to the simpler carrier-substitution method of
FIG. 1, the override audio and an optional override video signal
are superposed or overlaid on the program carriers, rather than
substituting them. The override signals are supplied to an
intermediate frequency modulator 17, passed to a splitting network
18 which raises and splits the signals to the requisite number of
frequencies channels. Each program override signal is switched
through a respective cable television modulator-processor 19 where
it replaces the program signal. The output of each modulator
processor is fed through the cable system's combining network 21
for transmission to viewers.
This method is much more costly than the carrier substitution
method because the override is effected separately for each channel
at channel frequencies which are typically in excess of 50 MHz
whereas the substitution carrier method employs a common RF
override.
An advantage of the more expensive channelized override approach is
the option of selectively overriding a predetermined number of
channels. However, a further drawback of this known channelized
override system is that the selection of channels to override is
fixed, being made permanently when the channel override hardware is
installed, and cannot be automatically or dynamically
redetermined.
A further advantage of the channelized approach is the provision of
an optional video output as an alternative to a blank screen. This
option requires additional equipment for each channel, for example
a text-character generator, or live video, if this is
available.
In general, the channelized override approach is expensive because
program-frequency override signals have to be created separately
for each channel, at the headend, means for which are not normally
a part of a cable television system's equipment. As reported by the
SCTE, cable stations do not generally have a source of live video,
although, in some cases, this may be delivered from an activating
authority.
Commencing at page 7 of their comments, the SCTE make proposals for
design parameters for a new emergency alerting device complying
with the proposed FCC requirements, or a close modification
thereof. Such a hypothetical device could, according to the SCTE,
be a universal device for AM and FM broadcast TV as well as cable
television, and should have card slots and optional modules to be
able to be tailored for diverse applications and user requirements.
Further according to the SCTE, a two-tone emergency warning
generator should not be necessary as this tone should be passed
through from a broadcast source, and the system should be
activatable by a telephone DTMF signal. A capability directly to
turn television sets on and off from an incoming cable signal was
seen as undesirable.
The hypothetical device would contain intelligence to code
addressable information and to act to activate override equipment
to pass through emergency information received. The device should
be programmable with regard to a rating of the seriousness or
impact of a given incoming alert or test, to determine the degree
of channel override. This alert level setting by local programming
should permit national activation. The device should be capable of
receiving emergency information from multiple sources, for example:
a CPCS-1 station; NLAA weather radio; state government; local
authorities such as the mayor, or city or county emergency
management office; or state police, local police or fire
departments and the like.
A basic device before options should have connections and
associated electronics to receive activation signals and emergency
information messages from the local NOAA weather radio frequency,
the local AM broadcast CPCS-1 frequency, and via a twisted pair
connection. The purpose of the twisted pair input is to enable
equipment in cable television headends which is currently
accessible to local authorities via telephone connections, to be
utilized.
Optional features could include additional inputs from audio and
video signals from external sources for example satellite,
microwave, or cable links, and AM or FM television broadcast.
Optional feature could also include a data port, for example, an RS
232 connection for receiving digitized signals and for those areas
having designated local emergency alerting frequencies, the
capability of adding an auxiliary RF receiver could also be
included.
The hypothetical specification continues with the parameter that
once a signal is received, by the device through any one of the
aforesaid inputs, the signal is decoded to retrieve address
information, implying that incoming signals from all input ports
need to be sampled by decoding circuitry. Recommended was the
ability to decode two types of signals, namely, standardized
digital encoding such as WRSAME coding implemented by NOAA weather
radio and DTMF telephone signals to permit utilization of existing
equipment.
The hypothetical device is further specified as having necessary
electronics and connections to support a contact closure output and
an audio output. The contact closure output would be activated in
response to an alert signal by the device to activate whatever
program override equipment is utilized by the participant. The
audio output would serve to pass through emergency information
transmitted by an activating entity.
Optional additional outputs include video output for an emergency
video signal; a digital output to feed ASCII text for video crawl
messaging; an additional data output port, for example an RS 232
and the necessary electronics could be included to provide
verification of receipt of an activation signal and of override of
programming; a printer or modem, or both.
All these characteristics are no more than desirable goals. No
engineering, no circuit design, no principles of design or
operation of a device that could comply with these elaborate
parameters, are disclosed or suggested by the SCTE.
Noting the proliferation of cable television channels, and that
this is a niche market with optimistic potential product runs only
in the low thousands, because of the number of cable television
systems to be supplied, new override equipment comprehensively
meeting all the FCC and SCTE parameters is expected to be extremely
costly, so costly as to be prohibitively expensive for smaller
cable television facilities, such as those with fewer than a
thousand subscribers.
SUMMARY OF THE INVENTION
The present invention solves a problem. It solves the problem of
providing an economical cable television messaging system that can
override or substitute a video message on a multi-channel cable
television system in a selective manner suitable for delivering
public emergency alert information to practically any member of the
cable television audience.
The above problem is solved by an inventive system which is readily
able to receive emergency alerting, or other, messages from
multiple sources and to be activated by remote electronic signals,
for example, personal computer output or DTMF touch-tone telephone
input.
In accordance with the objective of solving one or more of the
foregoing problems, the invention provides a cable television video
messaging system for selectively overriding a desired input message
onto multiple channels of a cable television system having a
headend system where multiple external program signals are
channelized by means of individual channel modulators having
program signal input ports and exported to cable for transmission
to a subscriber audience. The inventive video messaging system
comprises:
a) a remotely activatable input message decoder to receive, from
multiple sources, incoming message information regarding a video
message to be overlaid on at least one channel, said message
decoder decoding message descriptors embedded in or accompanying
said incoming messages;
b) an intelligent message-management device for routing messages to
at least one designated channel according to said message
descriptors and in accordance with system-based instructions;
and
c) a video injector to combine said message video with program
video for said designated channel to produce a channelized combined
video message;
wherein said channelized combined video message is supplied to said
channel modulator program input port.
Preferred embodiments employ a digital supervisory and display
management system that can be embedded on existing program
distribution equipment in a cable television system's headend
facility. The invention extends to a headend facility equipped with
the inventive video messaging system.
Surprisingly, I have found that, although low cost is an important
consideration in making my invention, the expense of digitizing the
message input and then separately converting each channelized
output to an analog signal output compatible with the program
signal, is more than outweighed by the benefits gained. In
particular, by employing microprocessors in conjunction with
significant data storage capability linked to one another in a data
network, the embedding of a digital loop to control an analog
processing system brings with it the advantages of digital control.
Surprisingly, within the confines of a low-cost, moderate
production volume system, I am able to gain the advantages of
computer control, along with software programmability of many of
the system functions.
A major difficulty in bringing the advantages of inserted video
messages to multi-channel cable television systems, lies with the
expense of providing separate messaging equipment for each channel.
This difficulty is compounded in attempting to bring the benefits
of computer management to a cable television headend facility.
While the cost of a centralized personal computer used to perform
control functions at the headend, which cost will probably be
several thousand dollars when allowance for specialized video or
audio-video boards is made, may not be unreasonable, the cost of
servicing every one of tens of channels with personal computer
equipment may be prohibitive.
A further difficulty in providing computer management of cable
headend facilities lies in the difficulty of devising suitable
interfacing between control systems operating in a digital domain,
and tens of continuously supplied video program signals processed
in an analog domain, while ensuring that digital control, or
supplementation, does not result in unintentional interruption of
any program signal. This problem is also solved by the systems of
the invention. These advantages are achievable by employing
microprocessor units programmed preferably in an assembly language
and wired together, through communications interfaces, or otherwise
in communication, so that physically separated units can talk to
one another to interchange addressed digital data packets. Thus, in
a preferred embodiment, the invention provides a
microprocessor-equipped message-management unit, or with inputs for
receiving a variety of coded or decoded message management
information. The message-management unit outputs messages,
preferably in digital form, labeled with one or more channel
addresses according to what channels have been designated to
display a given message.
Receiving channels are each equipped with a channel message unit to
receive a message addressed for that channel, in digital format,
and to overlay or substitute that message, in analog form, on the
program video output. Preferably, the channel units each have an
audio and a video connection with a modulator unit for that
channel. These connections can be with customary jacks, for
retrofitting or, alternatively, the channel units could be built
in, or incorporated with the modulator units, as original
equipment.
Channel message units according to preferred embodiments of the
invention are also microprocessor equipped and recognize
appropriately addressed messages from the message-management unit.
A further problem in messaging multiple cable television channels
is that television channels are asynchronous. This means that an
overlaid moving text cannot be put out in a common format to every
designated channel. Preferred embodiments of the invention solve
this problem by providing synchronization means in each channel
unit to synchronize a message signal to the channel's horizontal
and vertical characteristics.
The message-management unit is preferably adapted to receive the
message management information from multiple sources. The message
management information can include message content, or location
information specifying where the message content is to be found,
along with prioritizing or rating information from which the system
can, according to predetermined inputs, select a channel or group
of channels on which to display the message.
In general terms the CATV messaging system of this invention
provides a digital supervisory and message display system embedded
on or overlaid on top of the conventional video signal distribution
system of a cable television service.
In preferred embodiments, channel units are connected to a
message-management server to form a distributed local area network
within the cable headend, and are positioned as a unit to receive
normal cable television system input and to output to the cable
system.
While the invention is applicable to the distribution, in a
selective manner, of one or more incoming audio messages, among
desired cable television channels, without an accompanying video
message, preferred embodiments employ the enhancement of video to
improve the message's impact, and therefore effectiveness, on the
viewer, and to enhance the value of the equipment to the cable
television service. Bearing in mind that emergency alerting systems
are subject to regular testing, it is important that the message
form be acceptable to most viewers, and not unduly annoying.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Some embodiments of the invention will now be described, by way of
example with reference to the accompanying drawings, in which
similar reference numerals depict similar structural features,
and:
FIGS. 1 and 2 are conventional programming override equipments for
emergency alert massaging.
FIG. 3 shows a schematic layout of a cable television system's
headend system or headend facility equipped with a cable television
message system according to the invention;
FIG. 4 is a view similar to FIG. 1 of another embodiment of cable
television message system according to the invention which is more
suitable for larger facilities;
FIG. 5 is a view similar to FIG. 1 of a still further embodiment of
cable television message system according to the invention which is
more suitable for smaller facilities;
FIG. 6 is a front elevation of a channel message unit depicted
schematically in FIG. 4;
FIG. 7 is a rear elevation of the channel message unit of FIG.
6;
FIG. 8 is a schematic view showing a possible arrangement of
communications and power channels between a message-management unit
and channel message units;
FIG. 9 is a front perspective view of a message-management unit
depicted schematically in FIG. 4 or FIG. 5;
FIG. 10 is a rear perspective view of the message control unit of
FIG. 9;
FIG. 11 is a schematic view of one possible physical disposition of
the channel message units of the inventive system, at a cable
television headend facility;
FIG. 12 is schematic or block diagram of a programmable,
intelligent, audio-video injector unit, which can function either
as a message-management unit or as a channel message unit in the
preferred embodiments of the invention described with reference to
FIGS. 3-11, depending upon how it is programmed; and
FIG. 13 is a circuit diagram of the intelligent audio-video
injector unit of FIG. 12.
The cable television messaging system shown in FIG. 3 is intended
for distributing Emergency Broadcast System alerting bulletins or
other messages in audio and video form. Preferred embodiments
receive a digital message and output the message as a video text
crawl on multiple selected channels. The inventive system decodes
incoming messages or message alerts received from a variety of
possible sources, determines which channel or channels should
receive each message and routes the message accordingly. The
inventive system can also generate message video to override, or
combine with, base band program video signals.
According to the invention, these steps are carried out prior to
modulation of individual channel signals, and a message-bearing
combined signal is supplied to each one of a cable television's
customary headend system's channel modulators, for the channels
designated to receive a particular message.
A feature of the invention lies in intercepting program signals
prior to each channel modulator, and selecting the modulator
program signal input port as a point of insertion for the supply of
a messaged program signal. A preferred embodiment employs
individual channel message units for this purpose, and preferably
these channel units are controlled by a centralized
message-management unit with which the channel message units
communicate, which message-management unit supplies addressed
message information, including, possibly, message content.
Overall system cost can be controlled by minimizing the functional
requirements of the channel units, moving as much functionality as
practicable to a centralized message-management unit. For most
services with substantial numbers of channels, reducing the cost of
the channel units, which are needed one for each channel, will
represent a significant saving in delivering a quality video
message to selected channels.
Referring to FIG. 3, the inventive cable television messaging
system shown comprises a message control decoder 20 which is
connected or connectable to receive a variety of communications
inputs, for example digital signals embedded within a broad casted
signal received from an AM receiver 22, an FM receiver 24, a
microwave receiver 26 and a satellite receiver 28 as well as DTMF
control signals and audio overlays via a telephone modem 30. Any of
these communications inputs 22-30 can carry an incoming emergency
alert signal or other incoming message overlay signal, (which may
be a substitution signal completely rather than partially replacing
the base program signal) to the message control decoder 20. While
at the time of this application, these inputs are usually in analog
form, it is expected that emergency alerting messages in
particular, may be disseminated in digital format in the future,
which digital messages can also be received by the decoder or other
components of the present invention.
Message control decoder 20 decodes address and control information
associated with an incoming message overlay system and relays the
message overlay system to a designated channel or channels through
a channel message inserter 32. Channel message inserter 32 also
receives channel program information from channel inputs CH-2, CH-3
to CH-N, "N" representing the total number of television channels
provided by the cable television system, there being, as shown, one
channel message inserter per channel. Each channel message inserter
32 incorporates an audio switch to select between program and
message audio and outputs a channel signal to channel modulator
34.
The content of the output channel signal depends upon instructions
received from the message control decoder 20 and will comprise
normal program information until an override signal is detected by
message control decoder 20, whereupon the audio or video signals,
or both, that are output to a channel modulator, or modulators 34,
for a designated channel or channels, are overlaid or substituted
with an incoming, appropriately coded, message, for example, an
emergency alert. The output of channel modulators 34 is supplied to
a cable system, for distribution to subscribers, through a
television combining network 36, in conventional fashion.
To comply with FCC requirements intended to incorporate cable
television into the national Emergency Broadcast System, or a
renamed such system, audio switching to provide a voiced alerting
message overriding or replacing program audio, will be necessary,
but a video overlay is expected to be optional. However, greater
flexibility and product functionality is obtained by providing
means for each channel message inserter 32 to insert a video
message which can, preferably, be, or include, a text, especially a
crawl text moving horizontally.
If desired, a details message can be supplied to a preselected
cable information channel CH-X, via a details message inserter 38
activated from message control decoder 20. Other channels can carry
messages referring viewers to the details channel in the event of
an emergency.
The inventive CATV (cable television) message system embodiment
depicted schematically in FIG. 4, installed in a multi-channel
cable television headend, is suitable for large and medium-sized
cable television systems. The novel CATV message system provides
the ability selectively to override multiple channels with both
audio and video messages, especially for example, with emergency
alerting messages. Here, as with the FIG. 3 embodiment, individual
channel modulators 34 feed channel signals into a combining network
36. Message signals are received via an AM line 40 and an FM line
42, through a message control decoder 44, which functions as an
Emergency Broadcast System decoder and responds to emergency alerts
when these are received.
In this embodiment, management of audio and video message override
or insertion is shared between a centralized channel messaging base
unit or message-management unit 46, and individual channel message
units 48 connected on an open network with message-management unit
46 to receive addressed control and message information therefrom.
Preferably this information is digitized to be susceptible to
computer manipulation.
Message control decoders 20 and 44 are intended to operate in
accordance with FCC EBS device requirements and can be constructed
in any manner as will be apparent to those skilled in the art.
Some possible inputs to message-management unit 46 comprise the
decoded output from message control decoder 44 and cable system
audio and video message sources 50 and 52 respectively. Thus, for
example, the message control decoder may recognize what type of
message is coming in, full page, horizontal crawl, foreign
language, e.g. Spanish, etc, or perhaps, audio only.
Message-management unit 46 then determines what should be done with
the decoded message. For example, a Spanish-language message is
probably intended only for a Spanish-language channel, and is
so-designated by message-management unit 46.
In addition, message control decoder 44 can include a contact
switch actuator 54 to activate message-management unit 46, as well
as digital input from message control decoder 44, if appropriate,
for example over an RS 232 serial interface. A network, or direct,
PC interface connection 56 and a modem interface 58 can also be
provided, permitting the inventive channel messaging system to be
remotely managed under computer control, or to receive
instructions, or messages from a near or remote computer.
Message-management unit 46 can also output an activity log, message
copy or any other available information to a printer 60, if
desired.
Message management unit 46 can provide a direct analog audio and
video override signal to a details message channel 62, if
desired.
Message-management unit 46 uses intelligent digital means,
preferably a microprocessor, to manage distribution of incoming
messages to the designated channels.
Each channel message unit 48 is also preferably
microprocessor-equipped and has audio and video input connections
to receive program signals 64, and output audio and video
connections 66, to a respective modulator 34. Digital communication
with message-management unit 46 can be over an RS 485 link. Channel
message units 48 receive appropriately addressed digital messages
from message-management unit 46, convert a received message to
analog form, combine it with program video as appropriate, and
output the overlaid or substituted signals to their respective
modulators.
In an operational example, an emergency alert received by AM radio,
in analog form, is decoded, its priority or other coding is read
and passed to message-management unit 46 which interprets the
priority code, sends an audio message, for example, an emergency
official's voiced bulletin, also received over AM radio, to the
channels appropriate to that priority. Video messaging is
activated, digitized and sent out to the respective channel units
where the digitized message is synchronized for that channel and
output as analog and overlaid on the program signal, for example,
as a horizontal text crawl.
This system permits dynamic scripting on multiple channels. Simpler
systems suitable for emergency alerting can provide a single line
of text moving across an otherwise uninterrupted program screen.
More sophisticated systems can include a graphics processor in both
the message-management unit 46 and each channel control unit 48,
separately to drive screen sub-divisions or windows and can be
used, for example, to provide an onscreen window for passive, or
interactive advertising messages from sponsors of programming, or
for the cable system or channel to advertise its services or
programming, or to sell classified advertising and the like.
The FIG. 5 embodiment, intended for smaller cable systems, is
similar to the system described with reference to FIG. 4, except
that, here, instead of outputting to individual channel message
units, the output from message-management unit 46 is supplied to an
intermediate frequency (IF) modulator 68, operating for example at
44 MHz, which downloads the message audio and video on to all
channels for which the IF modulator 68 and CATV messaging system is
installed.
The FIG. 5 system is unable to synchronize message video for
individual channels, but provides a blank screen overlay on every
channel, or more preferably a static, full-screen text message to
accompany the audio message. It thus succeeds in supplying an
emergency alert or other message to a group of television channels,
being a group selected on installation, including both broadcast
and non-broadcast channels, broadcast implying a channel relayed
from a broadcasting rf station, via antenna pickup, which station
is assumed to be a member of the Emergency Broadcast System.
In one application, the FIG. 5 embodiment breaks into all channels
with a static (though possibly pageable) full-screen, preferably
textual displayed message accompanied by a voice-over, the same
messages being sent to all installed channels. If desired, the text
message can tell viewers to turn to a different channel for more
information about the emergency.
A suitable channel message unit 48, as shown in FIGS. 6-7, has, for
external communication, READY, ACTIVE and TEST indicator lights 70
on its front panel; and on its rear panel a daisy-chained or
serial-connected communications cable 72 networking to the
message-management unit 46 and other channel message units 48,
video input and output 74 and stereo audio input and outputs 76.
Power can also be carried in communications cable 72, employing
channels such as those shown schematically in FIG. 8.
FIGS. 9 and 10 show similar external communications for a
message-management unit 46 which has an additional video
input/output 78, and two serial data communications ports 80 with
data-present indicators 82 and a power cable 84.
FIG. 11 shows a message-management unit 46 networked to a plurality
of channel message units 48 mounted on racks (not shown) alongside
the channel modulators 34, each channel message unit 48 being
coupled, or wired to an adjacent modulator 34. Alternatively, the
message units 48 could be arranged side-by-side, one with one
another, on one or more racks. This may be more convenient when
retrofitting the invention by coupling the channel message units 48
to existing channel modulators 34 in a cable television headend
system.
The embodiment of FIGS. 12 and 13 exemplifies how a digital control
circuit, equipped with a supplemental image source of message video
can be embedded in a single unit with a base band video pathway to
inject a video message on to the base band video producing a signal
for a complex image having independently controllable image sources
for split-screen, window and similar effects, and in the
particularly preferred embodiment of the invention, for
horizontally crawling a text message across an otherwise
uninterrupted, continuously running program screen.
One way of programming the intelligent video injector is as a
channel message unit 48. In this application, message video
received in digital form is converted to a video signal
synchronized, or otherwise adapted to the requirements of an
intended cable television program channel, and output to a channel
modulator, or other individual distribution point for that
channel.
An alternative application of the intelligent video injector unit,
achievable by programming, is as a message-management unit 46. In
this case, a video message source or sources, is desynchronized, if
necessary, digitized, packaged, processed and addressed according
to an externally specified protocol, which can be derived from, or
be responsive to a remote incoming signal or instruction, and
output on a digital pathway for interpretation by channel message
units 48, or, in the case of the IF system of FIG. 5, for
interpretation by the IF modulator 68.
Other useful applications of the novel, intelligent video injector
of the invention will be apparent to those skilled in the art. As
will also be apparent from the following description, by employing
microprocessors, and chip-based functional elements to perform
individual video management and conversion roles, and by
programming the microprocessors to communicate with one another
along cabled data pathways, a compact economical unit, can be
assembled on a single board and supplied in a small box complete
with at least one data communications port and video input/output
jacks and the like.
Such novel system units can also manage distribution of an audio
message override to, control-message specified channels, for
example by driving a chip-based audio multiplexer from a central or
control microprocessor that also manages the video functions of the
intelligent video injector.
Referring to FIGS. 12 and 13, a central microprocessor 90 functions
as a control unit and communications center for both the digital
and analog system phases, interface to the analog phase being made
through one or more digitally drivable video chips for image
generation, synchronization and the like.
Central microprocessor 90 is liberally supplied with ROM 92, for
program storage and RAM 94, for processing usage. In a practical
embodiment for providing message of fixed page, multipage or a
video crawl, 32 Kb is adequate for both purposes. Use of an
application-programmed microprocessor avoids the cost and bulk of
employing a complete computer system or station at each network
node point. Use of assembler or machine language, which is a
preferred practice of the present invention, avoids difficulties
arising from limitations of, and equipment capacity requirements
of, operating and network systems, but does mean that off-the-shelf
software modules cannot generally be employed. Assembler or machine
language is highly efficient, imposing modest storage requirements
and contributing to the efficiency, compactness and economy of the
systems of the invention. An 8-bit commercially available
microprocessor, is suitable for use as control microprocessor 90,
for current text crawl applications.
External digital communication to central microprocessor 90 is
handled by chip-based communications interface 96, and proceeds
physically through a communications port 97, which is preferably an
RS 232 serial port for external communication with the inventive
messaging system. For communication, in network style, with other
video injector units, a port 130 and associated cabling, preferably
of RS 485 type, can be provided.
The common digital componentry provided in multiple video injector
units, such for example as a message-management unit 46 and
multiple, perhaps tens of, or even hundreds of, channel message
units 48, namely central microprocessor 90, external communications
interface 96 and port 97, with associated cabling or other remote
communication means, and RS485-type unit-to-unit communication,
coupled with ROM-stored programming enabling multiple
microprocessors 90 to "talk" to one another, provides a shared
network with distributed processing enabling common functions, such
as implementing addressing instructions to be centralized, other
functions, can be distributed to the channel units 48.
A video pathway extends between a video input jack 98 and a video
output jack 100, and includes a component-based video amplifier
circuit 102, a chip-based synch separator circuit 104, a character
generator 106 and an emitter follower 108. A character setup
circuit 110 interacts with character generator 106 to control its
video output. Character generator 106 and a chip-based delay line
112 which outputs to, or talks to, character generator 106 and
synchronizer setup 104, are controlled by, and communicate with
central microprocessor 90.
Character generator 106 is on efficient means of generating message
video for text crawl messages. If a more sophisticated message
image is required, character generator 106 can be replaced by a
graphics generator or other image generator or suitable video input
which can be digitized and then regenerated in channel-compatible
form through an appropriately equipped channel unit.
An audio pathway comprises a chip-based audio multiplexer 113,
controlled by and communicating with microprocessor 90. Audio
multiplexer 113 controls the passage of base band or program audio
between audio input jacks 114 and audio output jacks 116. Message
audio is received through message input jack 118 and output through
message output jack 120. The system provides switching circuitry,
including audio multiplexer 113, operating to switch between local
audio and external audio sources such as FCC or FEMA supplied
warning messages, as instructed by microprocessor 90.
In a message-management or server mode, such as to provide the
message-management unit 46, the novel, intelligent video injector
can additionally comprise one or more data ports for external
communication beyond the network, for programming or message input,
and can also comprise, on a common, or additional board, additional
input/output devices for receiving messages from multiple sources
and for different types of outputs including hard prints, activity
reports remote operator alerting and the like.
However it is received at message management unit 46, central
microprocessor 90 coordinates a message or messages with routing
information that may be preprogrammed in ROM, separately supplied
over a data channel, or coded into the video message. Messages are
labeled with desired address information, for example in channel ID
circuit 136, and any local processing instructions and output
through the communications link constituted by communications
interface 132, RS485 port 130 and associated cable links, to
data-sharing channel message units 48.
In channel message unit mode, as determined by its programming and
installation, the video injector receives appropriately addressed
messages through its communications link comprising communications
port 97 and communications interface 96 into RAM 92 of central
microprocessor 90.
Central microprocessor 90 coordinates and controls the insertion of
the desired message into baseband, program video received through
video input jack 98 and the output of the compound signal through
video output jack 100. For a horizontal crawl text message,
character generator 106 is supplied from RAM 94 with digital
message text for conversion to video characters.
Characters size are determined by information provided by
microprocessor 90 to the character generator 90. Character
generator 90 is synchronized to the intended channel's horizontal
and vertical characteristics by signals from the sync separator
104. Timing of the message, to flow the characters across the
screen is effected by delay line 112 acting on sync separator 104
and character generator 106 under the control of microprocessor
90.
The microprocessor and chip-based systems of the invention have
been found to produce excellent quality text crawl messaging. As
compared with character generation at a broadcast station picked up
and relayed by a cable television service, messaging generated by
the herein described systems of the invention gains quality, (or
avoids airwave quality losses) from direction injection into the
cable distribution system, which is often fiber optic.
Received message audio is routed through multiplexer 113 to
specified channels, as designated by central microprocessor 90. If
desired, multiple messages can be synchronized to multiple,
different screen regions to create a composite message screen or
composite image screen made up of a base band image and a plurality
of injected images. As at present envisaged, multiple video
injector devices will be needed for each channel, one for each
added image segment. However, advances in processing equipment and
techniques, may enable multiple image segments to be processed
simultaneously.
A further advantage of the invention is an ability to sense the
presence of a video carrier signal on any one or more channels. If
microprocessor 90 reports that no signal is present, indicating a
loss of video on that channel, a substitute default video text
message can be automatically inserted by the messaging systems
described herein, for example, "Please Stand By. Normal programming
will resume as soon as possible."
It may be seen from the foregoing disclosure that, rather than
significantly modifying a cable television service's equipment, the
inventive messaging systems provide a digital supervisory and
display system for the cable television service which system can
easily be embedded on top of existing, analog-processing, program
distribution systems.
The digitally based control and display systems for cable
television facilities provide much more than just a new ability to
distribute emergency alert messages, they provide cable television
system operators with new means to control and manage their headend
facilities. The channel message units can not only insert messages
but, with suitable programming, and the addition of diagnostic
circuitry, because they read the program signals and have the
ability to communicate centrally in digital format, can provide
detailed and extensive on-line reporting of channel activities
including program signal quality characteristics, signal strength,
interruptions, changes and the like, as well of course as usage of
the messaging, which, if paid, can be used for billing
sponsors.
While an illustrative embodiment of the invention has been
described above, it is, of course, understood that various
modifications will be apparent to those of ordinary skill in the
art. Such modifications are within the spirit and scope of the
invention, which is limited and defined only by the appended
claims.
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